Subject: Re: DHCP client

From: Ralph Droms <[email-masked]>
Date: Thu, 02 Mar 2000 09:20:25 -0500

I mostly agree with what you've written, except for the very last sentence:

>So basically
>your DHCP client computer will have a valid IP address
>untill the lease expires, but it will not be able to
>participate in a TCP/IP session.

In the event that the DHCP client cannot contact a server, the client will 
have a valid address until the lease expires, and it *will* be able to use 
TCP (in fact, it can make full use of the entire TCP/IP suite).

- Ralph Droms

At 08:44 PM 2/24/00 -0800, Cody Smith wrote:
>   Mr.Schneider is exactly right in what he said, but
>there is more.  If a DHCP client is leased an IP
>address for a certain time period that client will
>keep the DHCP configuration information in its
>registry.  If upon startup the DHCP client does not
>recieve a reply to its DHCPrequest message which is
>sent out everytime the computer is restarted, it will
>still hold the original lease in its registry.  When
>50% of the lease time expires the DHCP client will
>request a DHCP lease renewal directly from the
>originating DHCP server.  When it cant find a DCHP
>server it will keep on sending out DHCPrequest
>messages directly to the server from where the lease
>was first obtained, in certain specified intervals
>which are as follows:
>4 DHCPrequest messages in the first 5 minutes of
>startup, and 1 DHCPrequest message every 5 minutes
>thereafter.
>When the 87.5% of the clients lease has expired, and
>the DHCP client still cannot find the originating DHCP
>server is will send out a DHCPdiscover message which
>will basically broadcast to every DHCP server on the
>subnet if there is more than one DHCP server.  Keep in
>mind while all this is happening the client still
>holds on to that valid TCP/IP configuration(including
>a valid IP address) in the registry.  So basically
>your DHCP client computer will have a valid IP address
>untill the lease expires, but it will not be able to
>participate in a TCP/IP session.
>
>Cody Smith
>Network Administrator
>US Army
>FT. Lewis, WA 98433
>
>
>
>=====
>The only good is knowledge, and the only evil ignorance.
>-Socrates
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